Hot water boiler



Filed Feb. 6, 1956 May 19, 1959l n H. vo-RKAUF- HOT` WATER BoILER 2 sheets-sheet 1 INVENToR.

HEINRICH VOR/(AUF ATTORNEY "la" 22A May 19, 1959 H. voRKAUF 2,887,096

HOT WATER BOILER FiledvFeb. e, 1956 2 sheets-sheet 2 A IN VEN TOR.

HE//vR/CH VOR/AUF BY i /vmz ma;

ATTORNEY United States Patent HOT WATER BOILER Heinrich Verkauf, Berlin-Schmargendorf, Germany Application February 6, 1956, Serial No. 563,78)

wClaims priority, application Germany February 17, 1955 8 Claims. (Cl. 122-235) The invention relates to `a high pressure hot water boiler and more specifically to Ia hot water boiler with tubular frame-work including vertical tubes, such as corner tubes, particularly for high output. In heating systems with boilers of the mentioned type, pumps are rusually inserted in the pipe -line between the system and the boiler in order to circulate the heated water from the boiler through the heating devices of the system and back through the boiler. In such systems, owing to the friction in the boiler `and other parts through which the water circulates, the pressure drop is very considerable. Since the friction head of the pump will be increased as the vpressure drop through the boiler increases, it is imperative to reduce the pressure drop to a minimum.

Therefore, it is an object of the present invention to provide a boiler of the mentioned type in which the friction is considerably less than in the conventional boilers for the same purpose in order to reduce `the friction head and, thereby, the horsepower of the electric motor required bythe circulating pump.

Further, `another object of the invention is to provide a boiler through which natural circulation will take place should, for any reason, the circulating pump of the heating system fail, and this natural circulation will be the greater `the lower the pressure drop or friction head is in the boiler.

The invention further aims to divide the boiler tube assembly as near as possible into two equal circuits to maintain thereby a substantially equal circulation in these circuits whereby the length of the water travel in the boiler tubes will be -reduced and the eifective heat transfer will be increased.

In my copending application Serial No. 366,761 of July 8, 1953, I have disclosed a hot water boiler for a heating system in which the friction head is substantially reduced as compared with boilers of conventional types. In the boiler according to the mentioned earlier application, the water pumped by a circulating pump from the heating system enters a convection heating surface and flows on to a radiation heating surface of the boiler from where it is supplied to the heating system while a portion of the hot water can return from the collectors to the distributors of the radiation heating surface through two corner tubes of the boiler frame work.

Contrary, thereto, and in order further to reduce the friction head and pressure drop and, consequently, the required power ofthe electric motor driving the circulating pump, the present invention essentially provides a boiler in which four corner tubes of the boiler framework are utilized forrconveying the circulated water from the collector or collectors of the weakly heated convection heating surface `to the distributors of the radiation heating surface, wherein fthe collectors are `located .on a high level `andthe distributors on `a low level.

This arrangement is highly advantageous because owing to the entrance of the only weakly heated return wa- "ter into the corner tubes, serving as return `tubes for the "ice 2 intensely heated radiation heating surface, the water temperature in the corner tubes `must always be lower than in the tubes of that surface whereby -the gravity circulation, which is superimposed on the artificial circulation, will be enhanced.

Further objectsl and details of the invention will jbe apparent from the description given hereinafter and `the accompanying drawing illustrating embodiments thereof by way of example.

v In the drawing:

Fig. 1 is a diagrammatical cross-section of a boiler according to the invention, a heating system which may be served by the boiler being indicated in. dash and dot lines,

Fig. 2 is a diagrammatical partial cross-section along line 2--2 of Fig. 1,

Fig. 3 is a diagrammatical longitudinal cross-section of another embodiment.

Referring now to the drawing in Figs. 1 and 2, the boiler comprises a framework with vertical front corner tubes 10 and rear corner tubes 10', the conventional bricliworlc being indicated `at 11. The boiler may be of any suitable and `conventional type. In the embodiment laccording `to Figs. 1 and 2, a boiler of the flat grate `type is shown, the grate being denoted by 12. A partition 13 extends upward between the furnace space 14 and a flue 15 in `which the convection heating `surface is ar ranged. The arrows indicate the flow of the combustion gases. A `heating system H, to be supplied by the boiler with hot water, is indicated in dash and dot lines and comprises the circulating pump P.

The radiation `heating `surface of the boiler consists of the vertical front tubes 16, side tubes 17, and rear wall tubes 18. The front wall tubes 16 are bent in their upper part to form the ceiling tubes 19. The front and ceiling tubes are connected to the lower distributor 20 and to the upper collector tube 21, which is connected to the upper ends of the corner tubes 10. The rear wall tubes 18 are connected to the ceiling tubes 19 with `which they have the collector tube 21 in common; they extend upward from the distributor 22. The sidewall tubes 1,7 of each side extend upward from a distributor 23` lwhich is connected to the corner tubes 10 and lll of the same side and also to `the distributor 22. The upper ends of the side wall tubes of each side are connected to a collector 24 which is jointed to the corner tubes `10 together with the aforementioned collector 21, and which is also connected to the corner tube 10 of the same side. The collector `tubes 21 and 24 have a common outlet through the branch 25 which serves for connecting the boiler to the heating system H.

The convection heating surface in the space 15 consists of serpentine tubes 26 which extend 'between a lower distributor 27 and an upper collector 28, both being located outside the `boiler wall 11. Collector 28 has longitudinal `extensions 29 along the sides of the boiler which extensions communicate through short arms or branches 30 and 31 with the corner tubes 10 and 10', respectively, a short distance underneath the aforementioned collectors 24. The distributor 27 receives the return Water from the heating system H.

In the operation of the boiler, the return water from the `heating system `H will be pumped into the distributor 27. The serpentine tubes 26 extend from the distributor 27 lupwards inthe downwardly directed llue 15 and constitute a relatively weakly `heated convection heating surface protected against radiation by the wall 13. VThey are joined to the collector 28. The 'water collected `in the `pipe 28 will ow through the longitudinal extensions 29 'and the branches 30 and 31 into the corner tubes .10 `and 10', `from where 4the water will be ydistributed into the `distributor tubes 20, `22 and 23. Thus,

, 3 the corner tubes 10 and 10' serve as conduits to conduct the return water, which has been weakly heated in the tubes of the convection heating surface to the intensely heated tubes 16, 17 and 18 of the radiation heating surface, from where the hot water ows through the collectors 21, 24 and branch 25 to the heating system H.

Owing to the introduction of only partly heated return water, a mean temperature Will exist in the corner tubes 10 and 10' which, independently of the boiler load, will always be lower than the average temperature of the water in the intensely heated tubular system so that an increased ygravity circulation will take place superimposed on the forced circulation. This is particularly so because the pressure head will be greatly reduced owing to the fact that the weakly heated return water enters the radiation heating surface from both ends, the front as well as the rear, that means, through all four corner tubes 10 and 10'. Another advantage of the boiler according to the invention consists in that a gravity circulation will be maintained through the tubes of the radiation heating surface, collectors 24 and 21, corner tubes 10 and 10' and distributors 20, 22 and 23, even if the circulating pump P of the heating system H should fail for any reason. lf, under such circumstances, the water in the convection heating system remains stagnant, there is no danger of the serpentine tubes 26 burning out as they are only weakly heated by the 'gases passing through the flue 1S. n

In the embodiment of Fig. 3, a one tiue hot water boiler is shown. The furnace space is again enclosed by groups of tubes 40, 41 and 42 which extend from the lower distributors 43, 44 and 45, respectively. The groups of tubes 40 and 41 are joined and communicate with the collector 46 which is connected to the longitudinal collectors 46' of the side wall tubes. tical corner tubes 47 and 48 of the boiler frame work serve as return pipes for the ygroups 40, 41 and 42. Above the furnace space 50 and protected by tubes 40 against radiation, the convection heating surface is located which consists of two groups of serpentine tubes 51 and 52. Both these groups extend from a distributor 53 which is to be connected to the discharge from the heating sytem. The distributor S3 is preferably located between the front corner tubes 47. However, if so desiredit may be arranged on the outside of the boiler as shown with respect to the similar distributor 27 in Fig. '1, as there is no communication between these distributors and the adjacent corner tubes. The tubes 51 and 52 communicate with transverse collectors 54 and S5,

respectively, which are connected to the upper ends of The ver- Cit `to the mentioned collectors by means of tubes 58 which V n are elastic in order to yield to dierent elongations due to heat. Owing to this connection a mean temperature will prevail in the corner tubes 48 which is higher than that inthe front corner tubes.

It will be clear that the advantages stated with referenceto the boiler of Figs. l and 2 also exist in the boiler according to Fig. 3 and that, if the circulating pump of the heating system fails, a gravity circulation will stili prevail in the intensely heated groups of tubes through therear corner tubes which act as return tubes.

It will be apparent to those skilled in the art that many alterations and modifications of the structure illustrated and 4described are possible without departure from the essence and spirity of the invention which for that reason shall .not be limited but by the scope of the appended claims. Particularly wherever in the specification and Vclaims corner tubes have been mentioned, other vertical Etubes ifpresentn, thev boiler frame-.work may be used for the connection between the convection and the radiation heating surface.

I claim:

l. A hot water boiler for a heating system which includes a pump for circulating water through said system and said boiler, comprising a tubular frame-work including at least four vertical tubes, a rst heating surface including rst' distributors, iirst collectors and groups of tubes connected to said rst distributors and first collectors and being intensely heated predominantly by ra diation, said first distributors being connected to the lower portion of said vertical tubes so that there is communication between all said first distributors and all said vertical tubes, a second heating surface less intensely heated than said first heating surface and including second distributor means, second collector means, and located above said second distributor means serpentine tubes connecting said second distributor means to said second collector means, said second distributor means being adapted to receive return water from said heating system and said second collector means being connected to said four vertical tubes adjacent the upper ends of the said vertical tubes at an appreciable distance above said first distributors so that said return water being heated by said second heating surface flows down through all four vertical tubes to said rst distributors.

2. A boiler as claimed in claim 1, said second collector means comprising two second collectors, each one of said second collectors being connected to two of said four vertical tubes.

3. A boiler as claimed in claim l, further comprising at least two return tubes connecting said rst collectors to at least two of said four vertical tubes.

4. A boiler as claimed in claim l, further comprising at least two return tubes connecting said first collectors to at least two of said four Vertical tubes, at least one of said iirst collectors being transverse in respect to said boiler and including a hot Water discharge branch, said return tubes ,being arranged underneath said transverse collector.

5. A hot water boiler for a heating system which includes a pump for circulating water through said system and said boiler, comprising four vertical frame-work tubes detining the corners of a vertical shaft, two first longitudinal and one first transverse distributors along three sides of said shaft and connected to the lower end portions of said corner tubes, two first longitudinal and one transverse collectors co-ordinate with said first distributors, respectively, on a level above the upper ends of said corner tubes, a second distributor connected to the corner tubes opposite to and on a level higher than said first distributor, groups of substantially vertical pipes connected to the co-ordinate collectors and distributors, a group of ceiling pipes connected to said second distributor and said vertical pipes opposite said second distributor so as to divide said shaft into a lower furnace space and an upper hue space, a third distributor on a side of the lower portion of said iiue space, two second collectors connected to opposite pairs of said corner tubes adjacent the upper ends of said corner tubes and on a level above said third distributor, and two sets of serpentine tubes connecting said second collectors, respectively, to said third distributor, means to connect said second transverse collector to an inlet, and means to connect said third distributor toan outlet of said heating system.

6. A boiler as claimed in claim 5, further comprising two deaerating tubes each connecting the upper end of one of the front corner tubes to the free end of the ad jacent first longitudinal collector.

7. A boiler as claimed in claim 5, further comprising two curved return pipes each connecting one of the first longitudinal collectors to one of the rear corner tubes underneath the point of connection of the second collector.

8. A hot water boiler for a heating system which includes a pump for circulating Water through said system and said boiler, comprising a frame-work including four vertical corner tubes, a radiation heating surface including first distributor means connected to said four corner tubes, and collector means adapted for connection to the inlet of said heating system, and a convection heating surface including second distributor means adapted for connection to the outlet of said heating system, and second collector means located above said rst distributor means and being connected to said four corner tubes References Cited in the le of this patent UNITED STATES PATENTS McNulty June 19, 1928 FOREIGN PATENTS Belgium Mar. 31, 195() 

